I don't know if all the gymnastics floors are blue now. All the ones I've competed on have been blue though.
Here are some interesting ones:
Li Chunyang floor 1986 Goodwill Games AA
[youtube]5dEV_yFciZg [/youtube]bright yellow!
Svetlana Khorkina - 1994 Goodwill Games EF - Floor Exercise
bright pink! pretty! they even say: the floor mat is pink, don't adjust your television set! lol